DOLFIN

Matrix Addition

Asked by Pietro Maximoff on 2010-01-01

Hello

How do I add two matrices together using the C++ interface, i.e, A = M + K ?

The Matrix class has no function for this and axpy doesn't seem like the right one to use.

Best wishes

Pietro

Question information

Language:
English Edit question
Status:
Solved
For:
DOLFIN Edit question
Assignee:
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Solved by:
Johan Hake
Solved:
2010-01-02
Last query:
2010-01-02
Last reply:
2010-01-01
Best Johan Hake (johan-hake) said : #1

On Friday 01 January 2010 12:57:47 Pietro Maximoff wrote:
> New question #95871 on DOLFIN:
> https://answers.launchpad.net/dolfin/+question/95871
>
> Hello
>
> How do I add two matrices together using the C++ interface, i.e, A = M + K
> ?

The operator+ is not implemented in the C++ interface. You can do something
like:

  Matrix A(M);
  A += K;

or

  Matrix A(M);
  A.axpy(1.0, K, true);

if you know they have the same sparsity pattern.

Johan

> The Matrix class has no function for this and axpy doesn't seem like the
> right one to use.
>
> Best wishes
>
> Pietro
>

Pietro Maximoff (segment-x) said : #2

Thanks Johan Hake, that solved my question.